#include <iostream>
#include <vector>
#include <list>

class Single
{
private:
    Single()
    {
        std::cout << "single!!\n";
    }

public:
    static Single *getInstance()
    {
        static Single eton;
        return &eton;
    }
    void print()
    {
        std::cout << "xxxx\n";
    }
};

int main()
{
    Single::getInstance()->print();
    return 0;
}